// given a control patch and (u,v) values, find
// the surface point and normal
Point Bezier::bezpatchinterp(Patch patch, float u, float v, Point &n) {
Point p;
Point dPdu;
Point dPdv;
Point trash;
std::vector<Point> vcurve(4);
std::vector<Point> ucurve(4);
bool horizontal = true;
bool vertical = false;
// build control points for a Bezier curve in v
vcurve[0] = bezcurveinterp(patch.getCurve(0, horizontal), u, trash);
vcurve[1] = bezcurveinterp(patch.getCurve(1, horizontal), u, trash);
vcurve[2] = bezcurveinterp(patch.getCurve(2, horizontal), u, trash);
vcurve[3] = bezcurveinterp(patch.getCurve(3, horizontal), u, trash);
// build control points for a Bezier curve in u
ucurve[0] = bezcurveinterp(patch.getCurve(0, vertical), v, trash);
ucurve[1] = bezcurveinterp(patch.getCurve(1, vertical), v, trash);
ucurve[2] = bezcurveinterp(patch.getCurve(2, vertical), v, trash);
ucurve[3] = bezcurveinterp(patch.getCurve(3, vertical), v, trash);
// evaluate surface and derivative for u and v
p = bezcurveinterp(vcurve, v, dPdv);
p = bezcurveinterp(ucurve, u, dPdu);
// take cross product of partials to find normal
n = crossP(dPdu, dPdv);
n = n / n.length();
Point n2 = crossP(dPdv, dPdu);
n2 = n2 / n2.length();
p.saveNormal(n, n2);
return p;
}
inline void set_exp_vec_simd(F * dest, F f, F curve, unsigned int n)
{
vec<F> vbase, vcurve(curve * curve * curve * curve);
vbase.set_exp(f, curve);
unsigned int unroll = n / vec<F>::objects_per_cacheline;
do
{
detail::set_ramp<F, vec<F>::objects_per_cacheline>::exp_mp_iteration(dest, vbase, vcurve);
dest += vec<F>::objects_per_cacheline;
} while(--unroll);
}
